Preventing the complications of pregnancy that result from substance use (i.e., use of alcohol, illicit drugs and tobacco) during pregnancy remains a challenge. Each year in the United States, approximately 40,000 newborns are affected by fetal alcohol spectrum disorders. The United States also spends over $13 billion to address various needs of drug-exposed babies and approximately $300 million a year addressing pregnancy complications associated with smoking. Although most obstetric care providers report inquiring about alcohol and illicit drug use with their pregnant patients, a significant proportion of patients who use alcohol and/or illicit drugs do not admit this use. As this screening conversation may be the primary, and potentially only, method of identifying pregnant patients in need of additional intervention and support services for alcohol and/or illicit drug use, it is essential to understand how these conversations are occurring and whether certain communication styles are more likely to elicit disclosure and/or inspire positive maternal behavior change. The goal of the current proposal is to identify communication styles and processes that encourage pregnant, substance-using women to disclose this substance use and consider behavior change. This study seeks to both describe and begin to understand the associations between communication and substance use disclosure in obstetrics visits. First obstetric visits will be audio-recorded and transcripts examined to describe communication content, style, and processes used in discussions about substance use. Subjects who use alcohol, drugs and/or tobacco will return for qualitative interviews during which they will review their audio- taped conversation and describe their reactions. A particular focus will be on how the interaction influenced their willingness to disclose alcohol and/or drug use and impacted their motivation and ability to change their behavior. Obstetric care provider will also return for qualitative interviews explain their methods of addressing alcohol and/or illicit drug use during the first obstetric visit. Quantitative analysis will be used to explore associations between communication content, style and process in discussions of alcohol and drug use during pregnancy with women's disclosure of such use.